Hana Kazamaki, who often goes by the nickname Maki, is a central figure in her world, serving as the assistant to the young detective Yuu Asunaro. She is a woman in her twenties, with her birthday on January 5th, though she is notably secretive about her exact age. Hana has a petite and slender build, which, combined with her youthful face, leads to her frequently being mistaken for a teenager, a fact she secretly enjoys. She has mid-length blonde hair that she sometimes styles into twin tails or a bun, a departure from her natural black hair which she dyed after her previous career as an office worker. Her most distinctive article of clothing is a poncho, which she wears not just for style but specifically to conceal her chest, an aspect of her appearance she is self-conscious about.

In terms of personality, Hana is defined by her diligence and serious approach to her work, often being one of the few rational and grounded characters amidst a cast of eccentric detectives. Although her initial demeanor can come across as reserved and stoic, she gradually reveals a warmer, more expressive side, including an endearing clumsiness. She is deeply pragmatic, openly admitting that her motivation for taking her current job was its attractive salary rather than a passion for detective work. Despite this professional front, she has a softer, gentler nature, shown through her compassion for animals and her active involvement in a group dedicated to rescuing stray dogs. A significant part of her character involves a series of insecurities and quirks. She is notably self-conscious about her small chest, which she tries to conceal with her clothing and for which she drinks soy milk smoothies daily in the hope of a change. While she keeps her age a closely guarded secret, she is secretly pleased when people assume she is much younger, enjoying being mistaken for a student by her colleagues.

Before becoming an assistant, Hana led a varied professional life, having worked as a secretary, event hostess, bank employee, and even a croupier, which contributed to her broad and impressive skill set. As a high school student, she was eager to become an adult but lacked a clear direction for her future, feeling a sense of guilt about being a burden to her parents. Her entry into the detective world came through an audition for a television project, where she was selected to be Yuu Asunaro's assistant. In her role in the story, she is the indispensable support for her team, handling logistics, analysis, and a multitude of tasks with an efficiency that is admired by others. Her keen observational skills are particularly noted, especially her ability to see through disguises. Her work is so effective that the older detective Keiichiro Nagumo once joked that she could easily make a detective obsolete.

Her most significant relationship is with her employer, Yuu Asunaro, whom she deeply trusts and respects, addressing as Master. She shares a friendly dynamic with the veteran detective Keiichiro Nagumo, who highly values her capabilities. Hana also learns cooking from her female colleague Mashiro Nakanishi, building a bond over shared domestic experiences, and maintains a friendly if sometimes self-conscious rapport with the younger Azuha Hoshino, mindful of the age gap between them. Throughout the story, Hana undergoes steady personal growth. Starting as a more stoic and reserved figure, she becomes increasingly expressive, relatable, and comfortable with her colleagues. Her hidden talents and underlying kindness continue to emerge, allowing her to find an environment where her diverse abilities are finally appreciated despite the chaos that defines the detective agency. Her notable abilities extend beyond professional efficiency; she possesses high academic skill, having achieved the top level on a national English proficiency test, and there are hints in her past of being athletic, possibly from a sport or running club during her school days.